該樓層疑似違規已被系統折疊?隱藏此樓查看此樓

運行程序，不知道為何點插入數據按鈕會報錯，請萬能的吧友幫我看看，謝謝，不廢話，直接上代碼

MainActivity.java

package com.example.activity16;

import android.support.v7.app.ActionBarActivity;

import android.content.ContentValues;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class MainActivity extends ActionBarActivity {

private Button createButton;

private Button upDatabaseButton;

private Button insertButton;

private Button updateButton; //聲明

private Button queryButton;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

createButton =(Button)findViewById(R.id.createButton);

upDatabaseButton=(Button)findViewById(R.id.upDatabaseButton);

insertButton=(Button)findViewById(R.id.insertButton); //聲明

updateButton=(Button)findViewById(R.id.updateButton);

queryButton=(Button)findViewById(R.id.queryButton);

createButton.setOnClickListener(new CreateListener());

upDatabaseButton.setOnClickListener(new UpDatabaseListener());

insertButton.setOnClickListener(new InsertListener());

updateButton.setOnClickListener(new UpdateListener());

queryButton.setOnClickListener(new QueryListener());

}

class CreateListener implements OnClickListener{

@Override

public void onClick(View v) {

DatabaseHelper dbHelper=new DatabaseHelper(MainActivity.this,"tom_db", null, 1);

SQLiteDatabase db=dbHelper.getReadableDatabase();

//只用調用了這個方法，才會創建，打開數據庫

}

}

class UpDatabaseListener implements OnClickListener{

@Override

public void onClick(View v) {

DatabaseHelper dbHelper =new DatabaseHelper(MainActivity.this, "tom_db", null, 2);

SQLiteDatabase db =dbHelper.getWritableDatabase();

//更新數據庫的版本

}

}

class InsertListener implements OnClickListener{

@Override

public void onClick(View v) {

System.out.println("insert");

ContentValues values =new ContentValues();

values.put("id",1);

values.put("name", "jack");

//values.put("id",2);

//values.put("name", "lili");

DatabaseHelper dbHelper=new DatabaseHelper(MainActivity.this,"tom_db",null,2);

SQLiteDatabase db=dbHelper.getWritableDatabase();

//獲得一個可寫的數據庫

db.insert("user", null, values);

//調用insert方法，把數據插入數據庫中

}

}

class UpdateListener implements OnClickListener{

@Override

public void onClick(View v) {

System.out.println("update");

ContentValues values=new ContentValues();

values.put("name","Jim");

DatabaseHelper dbHelper =new DatabaseHelper(MainActivity.this,"tom_db",null,2);

SQLiteDatabase db=dbHelper.getWritableDatabase();

db.update("user", values, "id=?", new String[]{"2"});

}

}

class QueryListener implements OnClickListener{

@Override

public void onClick(View v) {

DatabaseHelper dbHelper =new DatabaseHelper(MainActivity.this,"tom_db",null,2);

SQLiteDatabase db=dbHelper.getReadableDatabase();

Cursor cursor =db.query("user", new String[]{"id","name"}, "id=?",new String[]{"1"}, null, null,null);

while(cursor.moveToNext()){

String name=cursor.getString(cursor.getColumnIndex("name"));

System.out.println("query------>"+name);

}

}

}

}

DatabaseHelper.java

package com.example.activity16;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper{

private static final int VERSION=1;

public DatabaseHelper(Context context, String name, CursorFactory factory,int version) {

super(context, name, factory, version);

}//在SQLitOpenHelper的子類中，必須有該構造函數

@Override

public void onCreate(SQLiteDatabase db) {

//創建一個數據庫

System.out.println("create a DataBase");

db.execSQL("create table user(id int name VARCHAR(20))");

//execSQL函數用于執行SQL語句

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

System.out.println("updatabase");

}

}

關于布局的XML文件我就不發了，請大神指點